题目

A child who has once been pleased with a tale likes, as a rule, to have it retold in almost the same words, but this should not lead parents to treat printed fairy stories as formal texts. It is always much better to tell a story than read it out of a book, and, if a parent can produce what, in the actual situation of the time and the child, is an improvement on the printed text, so much the better. A charge made against fairy tales is that they harm the child by frightening him or making him sad thinking. To prove the latter, one would have to show in a controlled experiment that child16．关于路程和位移，下列说法中正确的是（　　）A．质点的位移为零，说明质点没有运动B．质点通过的路程不同，但位移可能相同C．质点发生了一段位移后，它通过的路程可能为零D．质点做直线运动时，其路程就是位移的大小